Electrical system



R. J. WENSLEY.

ELECTRICAL SYSTEM.

F1LEDMAR,14,1918.

WETNESSES:

lNVENTGR i ATTORNEY Patented dan. 16, 1923. i

UNITED STATES PATENroFFlcE.

RCY J'. "WENSLEY, OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A ACORPORATION SYLVANIA.

ELECTRICAL SYSTEM.

To all whom it many concern:

Be it known that I, Roir J. WENSLEY, 'a citizen oit' the United States, and a of Edgewood Park, in the county of Alllegheny and State of Pennsylvania, have invented. a new and useful Improvement in Electrical Systems, of which thefollowiig is a specification.

My invention relates to electrical systems and particularly to such systems in which a motor-started rotary converter is adapted to be automatically started and controlled for the purpose of supplying energy to the circuit under predetermined conditions.,

One object of my invention is to provide a system, of the above-indicated character, that shall be'readily applicableto existing types of motor-started rotary converters.

A further object of my invention is to,

provide a system, of theabove-indicated pensive to construct and eective in its operation. 't

In carrying out my invention, I provide means for energizing the vstarting motor of a motor-started rotary vconverter when the voltage on the system, that is to be supplied with energy from the converter, falls below a predetermined value. Means. is provided, that is dependent upon the current traversing the starting motor after it has once started, for connecting the converter, through.current-limiting devices, to the alternating-current circuit, and a polarized relay is adapted to short circuit the currentlimiting devices when the direct-current end of the converter is of such polarity that it may be connected to the direct-current circuit.

The single figure of ythe 4accompanying drawing is a diagrammatic view of an electrical system embodying my invention.

An electrical system in which my invention is embodied comprises an alternating- 'current circuit 1, a direct-current circuit 2 and a rotary or synchronous converter 3 connected therebetween. It is frequently vdesirable to cause the converter 3 to be started and stopped in accordance with predetermined load and voltage conditions in the direct-current circuit 2. If the converter 3 is located a relatively great dis-v tance from the source of alternating cur-l rent,v it is desirable that the starting and stopping of the converter shall be accomresidentv converter 3 can be caused .rupte'r- 4, "to lthe v to the collector rings character, that shall be simple and inexates, the circuit-interrupter 10 is plished byautomatic means, and, in so doin :the cost of operating the substations w11 be relatively small. vThat is, if the to operate only whena predetermined load is connected to the direct-current circuit, it will be understood that the only losses in the substation willoccur when the rotary converter is supplying energy.-

The conductors of the circuit 1 are operatively connected, through a circuit-interterminals of the primary winding 5 of a transformer 6, the secondary windings 7 of which are connected, through an automatically controlled switch 8, to the startingmotor 9 of the converter 3. 'The 'secondary winding 7 of the transformer 6 1s also connected, through a circuit-interrupter 10 and current-limiting devices 11,

' 12 `of the converter.

.A voltage-responsive relay 13 is operatively connected' tothe circuit -2 and is Y adapted, when the voltage on the circuit 2 drops below .a predetermined value, to complete a circuit 14, comprising the secondary winding 15 of a transformer 16, the primary' winding 17 of which'is connected across the circuit 1. The closing coil 18 of the circuitinterrupter 4 is connected across the circuit 14 and is thus energized to close the circuitinterrupter 4 when the voltage on the circuit 2 drops below a predetermined value by reason of the circuit 2 becoming heavily loaded. The actuating winding 19 of the switch 8 is connected across the circuit 14 through a switch 20 that is controlled by the circuit-interrupter 10. `That is, since the circuit-interrupter v10 is normally in its open -rupter 10. The circuit 22 is so connected tov the circuit 14 that, when the relay 21 operclosed. An interlocking device 24 is provided between the switch 8 and the relay 21 to prevent the operation of the relay 21 except when the'v switch 8 is closed to start the motor 9. However, when the current traversing the motor drops to a predetermined value to thereby 0F PENN- indicate that the motor 9 has accelerated to substantially synchronous speed, the spring 25 of the relay 21 will cause the contact members of the relay 21 to complete the circuit 22 and thereby effect the closing ofthe circuit interrupter 10 by means of a self locking relay 22'?. The closing of the interrupter 10 causes analternat1ng electromotive force of a relatively small value to be impressedon theconverter 3. When the in-A terrupter .10 closes,` the switchl 2O is opened to de-energize the winding 19 to disconnect started, if it pullsinto step with the circuit- 1 and the direct-current end is of the correct polarity, the movable member 31 of the con-V tact device 30 will turn in one direction and, when it engages the stationary contact member 32, it causes a relay 33 to be energized. Further movementl of the contact member 31 causes thesame to engage the stationary contact member 34 to efect energization of a relay 35. When the relays 33 and`35 are energized, a lcircuit is completed from the circuit 14 through the actuating winding 36 of a circuit-interrupter 37 that 1sadapted to short circuit the current-limiting devlces `l1. The relay 33 is emplo ed to lconnect the movable member 31 to t e circuit 14 so that the actuation of the relay 35 may be effected when the member 31 engages the contact member 34. When the contact member engages the contact member 34, the two contact members remain in engagement to maintain the relay 35 energized wherebyA the interrupter 37 is held closed by the coil 36.

Such engagement is maintained by reason of the de-energization of the polarity relay, by means not shown, after the interrupter 37 is closed. Thus, when the polarized relay 36 indicates that the direct-current end of converter 3 is of-such polarity that it may be connected, through a circuit-interrupter 38, to the circuit 2, the current-limiting -device ll will be short circuited to permit full -line current to traverse the converter 3.

However, if the polarized relay 36 indicates incorrect polarity, the contact member 31 will turn in the opposite direction to engage contact members-39 and 40 that are adaptedl to control means (not shown) to reverse thev field winding of the converter 3 and therebycause the same to slip a pole and have the and because it forms no partzof this inven tion except 1n that it is necessary to form a complete automatic substation.- Copend- 1n Seit. 27, 1916, by F. C. Hanker and C. M. Moss and assigned tov the Westinghouse Electrica Mfg. Co. discloses a ield-reversing arrangement of this type. After vthe converter 3 is connected to the circuit 2, if the voltage on the circuit 2 rises above a predetermined value, the circuit 14 will be interrupted and the' circuit-inten r'upter4 will be opened to therebyl disconnect the converter 3 from the alternating-current circuit. When the circuit 14 is opened, ,the circuit-interrupters 10 and 37return to their initial positions to permit the motor 9 of the converter 3 to be restarted when the desired conditions obtain rin the circuitr 2. v

My invention is not limited to the particular devices illustrated, as many modications may be made `therein without departingfrom the spirit'and scope of the invention as set forth in the appended claims.

I claim as my invention: I 1. In an electricalsystem, the combination with an alternating-current circuit, a direct-current circuit, a converter for operatively connecting the circuitsjtogether and a motor for starting the converter, of means for controlling the lenergization of the motor, means responsive `to the current application, Serial No. 122,377, filed l plication of a. relatively small 'electromotive 'force to the converter and means dependent uponthe polarity of the direct-current voltage of the converter `for controlling the ap plication of the normalgelectromotive Jforce to the converter. l

2. In an electrical system, the rcombination with an alternating-current circuit, a' direct-current circuit, a converter for operatively connecting the circuits together and a motor for starting the converter, of means for controlling the lenergization of the motor, means responsive to the current traversing the motor, meansv for limiting thel Icurrent that may traverse the converter'to a safe starting value, and means controlled by the motor-current-responsive means for tween the converter and the alternatingcurrent circuit.

, v3. In an electrical system, the combination with an alternating-current circuit, a direct-current circuit, a converter for opera- 'connecting the current-limiting means betively connecting the circuits togetherand a i motor for starting the converter, of means responsive to the voltage of the direct-current circuitfor controlling the energi'zation .ofthe motor and means responsive to the current traversing the motor andthe polar'ity of the converter for operatively conf necting the converter tothe alternating-current circuit.v

4. In' an electrical system, the combina'- tion Withoan alternating-'current circuit, a

direct-current circuit, a converter for operal rent circuit for controlling the energization of the motor, current-limiting devices, and means responsive to the dropv 1n current traversing the motor for operatively connecting the converter through the current-l limiting devices to the lalternating-current circuit. v l

5. In an electrlcal system, the combination with an alternating-current circuit, a" direct-currentclrcuit, a rotary .converter for operatively connecting the circuits together, and a'motor for starting theconverter, of means responsive to load conditions in the direct-current circuit for controlling the lstarting ofv the motor, current-limiting means, means responsive to a drop in current in the motor afterl it is started for con-l trolling the connection of the converter through the current-limiting means to the alternating-current circuit, and means `for short-circuiting the current-limiting means under predetermined polarityl conditions in the converter.

f 6. In an electrical system, the combination with an alternating-current circuit, a direct-current circuit, a rotary converterfor operatively connecting the circuits together,

vand a motor for starting the converter, of

meansresponsive to load conditions in the direct-current circuit for controlling thel starting of the motor, current-limiting means, means responsive to a drop in Acurrent in the motor after itis started for connecting the lconvertertthrough the currentlimiting means to the alternating-currentcircuit, and means comprising a polarized relay responsive to the polarity of the direct-current circuit and that of thedirectcurrent end of the converter for causing the current-limiting means to be shortcircuited.

7. In an electrical system, the combination with an alternating-current circuit, a

direct-current circuit, a rotary converter forl operatively connecting the circuits together, and a motor for starting the converter, of means responsive to load conditions in the direct-current circuit for-controlling the starting of the motor, current-limiting means, means responsiveto a drop in current in the motor after it is started for connec'ting the converter through the currentlimiting means to the alternating-current circuit, and means comprising a polarized relay responsive to the polarity of the di- 4rect-current end of the converter for causing the current-limiting means tobe short circuited.

8. Inv an electrical system, the combination with an alternating-current circuit, a

gizing circuit.

\\9. In an electrical system, the combination with an alternating-current circuit, a directcurrent circuit,'a rotary converter for connecting the circuits together, and a motor for starting the converter, a current-limiting means, means responsive to a` drop in currentiin themotor for connecting the converter through the current-limiting means to the alternating-current circuit, and means comprising a polarized relay,A responsive to the polarity of the vdirect-current circuit andl that ofthe direct-current end ofthe converter for causing the current-limiting means to be short circuite'd.

10. In an electrical system, the combination with an alternating-current circuit, a direct-current circuit, a converter for operatively connecting the circuits together and a motor for. starting the converter, of means responsive to a drop in the motor current for controlling the application of a relatively small valueof electromotive force to the converter, and -meansl for controlling the application of the normal electromotive force to the .converter under predetermined conditions of polarity therein. x

l1, In'an electrical system, the combination with an alternating-current circuit, a direct-current circuit, a converter for operatively connecting the circuits together and a motor for starting the converter, of means responsive to the current traversing the motor for controllingv the application 'of a 110 reduced voltage to the converter and means responsive to the polarity ofthe converter for controlling the application 'of the normal voltage thereto. n

12. In an electrical system, the combination with an alternating-current circuit, a direct-current circuit, a. converter for operatively connecting the circuits' together and a motor for starting the converter, of means responsive to a predetermined value of cur- 120 rent traversing-the motor for eil'ecting the connection ofthe converter to the alternating-current circuit and means for limiting the current that may traverse the converter to a safe starting value until a predetermined polarity is developed in the converter.

13. In an electrical system, the combination with an alternating-current circuit, a direct-current circuit, a converter` for operatively connecting the circuitsl together and a motor for starting the converter, of means` responsive to a predetermmed value of current traversing the motor for effecting i started synchronous converter which conthe conne'r'ztion of the converter to the alternatingcurrent circuit, means for hmltlng the current that may traverse the converter to a safestarting value and means responsive to the polarityof the direct-current end ofthe converter for rendering the currentlimiting means ineffective.

14. The method of starting a motorstarted synchronous convertenwhich' consists instarting the motor and thereby accelerating the converter to Substantially synchronous speed, connecting the converter to the alternating-current clrcuit through current-limiting reactors and then closecircuiting the reactors in accordance Withthe polarity of the direct-current end of the converter.l v

' 15. The method of starting a vmotorstarted synchronous converter which oonsists in starting the motor and accelerating the motor and the converterto substantially synchronous speed, simultaneously de-energizing the motor and connecting the converter to the alternating-current circuit to permit a current of small 'value to traverse the converter and then Ito permit normal values of current to traversethe converter 16. The method of starting a motorj sists in. starting themotor and accelerating the motor and the converter to substantially verter to the alternating-current circuit through current-limiting reactors until a -predetermined polarity is e'ected in the con.-

verter and then short-circuitingthe reactors. 17. The method of starting a vmotor- Y traverse the converter until. a predetermined polarity is developed therein and then to permit normal values of current to traverse the converter. u

In testimony whereof, I have hereunto subscribed my name this 12th day of March,

'ROY J. WENSLEY.

synchronous speed, simultaneously deeene'rglzmg the motor and connecting the con- -started synchronous converter which con-A 

